Use int which converts a string to an int, inside a list comprehension, like this:
desired_array = [int(numeric_string) for numeric_string in current_array]
Top answer 1 of 3
85
Use int which converts a string to an int, inside a list comprehension, like this:
desired_array = [int(numeric_string) for numeric_string in current_array]
2 of 3
60
List comprehensions are the way to go (see @sepp2k's answer). Possible alternative with map:
list(map(int, ['1','-1','1']))
Java2Blog
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Convert String Array to Int Array in Python [3 ways] - Java2Blog
December 25, 2022 - The eval() function accepts a Python string and evaluates it as a Python expression. We can use it in place of the int() function in the previous method. ... Use the map() function to apply the int() function to all elements of the array. Use the list() function to convert the map type object ...
How to convert string list to int list?
This is not how you would do this in Python. Any time you see code with range(len(something)), you know you are doing it wrong. The way to do it would be this: numbers = [int(num) for num in numbers] More on reddit.com
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June 4, 2023Convert string array into integer python - Stack Overflow
I need to convert following string array into integers. How to do it in python. More on stackoverflow.com
python - Converting a string to an array of integers - Code Review Stack Exchange
To make this work, we first throw ... numbers, we then make sure to explicitly convert those strings to numbers, using the int() casting function and list comprehension. ... \$\begingroup\$ You should refrain from using Python builtins names for your variables str, list and ... More on codereview.stackexchange.com
Converting a single line string to integer array in Python - Stack Overflow
I'm trying to learn python through HackerRank, and I've been stuck on reading stdin. The problem gives an array of integers as a single line of text formatted like: 1 2 3 4 5 This should become the More on stackoverflow.com
GeeksforGeeks
geeksforgeeks.org › python › python-converting-all-strings-in-list-to-integers
Converting all Strings in a List to Integers - Python - GeeksforGeeks
July 11, 2025 - map() function applies a given function to all elements in an iterable. Here, we use map(int, a) to convert each string in the list to an integer. ... List comprehension provides a more Pythonic and concise way to convert a list of strings to ...
Reddit
reddit.com › r/learnpython › how to convert string list to int list?
r/learnpython on Reddit: How to convert string list to int list?
June 4, 2023 -
numbers = input("Please type some numbers: ").split()for n in range(0, len(numbers)):numbers[n] = int(numbers[n])
Just tried converting a string list to an int list using a for loop and made this code but not sure what it means step by step, if someone could please explain the last 2 lines it would be much appreciated. Thanks!
Top answer 1 of 6
14
This is not how you would do this in Python. Any time you see code with range(len(something)), you know you are doing it wrong. The way to do it would be this: numbers = [int(num) for num in numbers]
2 of 6
6
First part is making a list. The split function will divide a string based on a character. By default it uses a space. You could split on other things by coding .split(‘,’) for example to divide on commas. The for loop is looping over the list and changing each list item to int. it’s using the index “n” in the loop to pull out each list item in turn. I’d use a list comprehension for that part though as I think it’s more readable. numbers_int = [int(item) for item in numbers]
Top answer 1 of 2
4
Use int with base=16 for conversion, and list comprehension for output list:
[int(num, base=16) for num in nums]
Example:
In [376]: nums = ['02', '01', '03', '01', '04', 'ab', 'cd']
In [377]: [int(num, base=16) for num in nums]
Out[377]: [2, 1, 3, 1, 4, 171, 205]
2 of 2
1
You can use a list comprehension for this
>>> data = ['02', '01', '03', '01', '04', '01', '05', '01', '06', '01', '07', '01', '08', '01', '09', '01', '0a', '01', '0b', '01', '0c', '01', '0d', '01', '0e', '01', '0f', '01', '10', '01', '11', '01', '12', '01', '13', '01', '14', '01', '03', '02', '04', '02', '05', '02', '06', '02', '07', '02', '08', '02', '09', '02', '0a', '02', '0b', '02', '0c', '02', '0d', '02', '0e', '02', '0f', '02', '10', '02', '11', '02', '12', '02', '13', '02', '14', '02', '04', '03', '05', '03', '06', '03', '07', '03', '08', '03', '09', '03', '0a', '03', '0b', '03', '0c', '03', '0d', '03', '0e', '03', '0f', '03', '10', '03', '11', '03', '12', '03', '13', '03', '14', '03', '05', '04', '06', '04', '07', '04', '08', '04', '09', '04', '0a', '04', '0b', '04', '0c', '04', '0d', '04', '0e', '04', '0f', '04', '10', '04', '11', '04', '12', '04', '13', '04', '14', '04', '06', '05', '07', '05', '08', '05', '09', '05', '0a', '05', '0b', '05', '0c', '05', '0d', '05', '0e', '05', '0f', '05', '10', '05', '11', '05', '12', '05', '13', '05', '14', '05', '07', '06', '08', '06', '09', '06', '0a', '06', '0b', '06', '0c', '06', '0d', '06', '0e', '06', '0f', '06', '10', '06', '11', '06', '12', '06', '13', '06', '14', '06', '08', '07', '09', '07', '0a', '07', '0b', '07', '0c', '07', '0d', '07', '0e', '07', '0f', '07', '10', '07', '11', '07', '12', '07', '13', '07', '14', '07', '09', '08', '0a', '08', '0b', '08', '0c', '08', '0d', '08', '0e', '08', '0f', '08', '10', '08', '11', '08', '12', '08', '13', '08', '14', '08', '0a', '09', '0b', '09', '0c', '09', '0d', '09', '0e', '09', '0f', '09', '10', '09', '11', '09', '12', '09', '13', '09', '14', '09', '0b', '0a', '0c', '0a', '0d', '0a', '0e', '0a', '0f', '0a', '10', '0a', '11', '0a', '12', '0a', '13', '0a', '14', '0a', '0c', '0b', '0d', '0b', '0e', '0b', '0f', '0b', '10', '0b', '11', '0b', '12', '0b', '13', '0b', '14', '0b', '0d', '0c', '0e', '0c', '0f', '0c', '10', '0c', '11', '0c', '12', '0c', '13', '0c', '14', '0c', '0e', '0d', '0f', '0d', '10', '0d', '11', '0d', '12', '0d', '13', '0d', '14', '0d', '0f', '0e', '10', '0e', '11', '0e', '12', '0e', '13', '0e', '14', '0e', '10', '0f', '11', '0f', '12', '0f', '13', '0f', '14', '0f', '11', '10', '12', '10', '13', '10', '14', '10', '12', '11', '13', '11', '14', '11', '13', '12', '14', '12', '14', '13']
>>> [int(i, base=16) for i in data]
[2, 1, 3, 1, 4, 1, 5, 1, 6, 1, 7, 1, 8, 1, 9, 1, 10, 1, 11, 1, 12, 1, 13, 1, 14, 1, 15, 1, 16, 1, 17, 1, 18, 1, 19, 1, 20, 1, 3, 2, 4, 2, 5, 2, 6, 2, 7, 2, 8, 2, 9, 2, 10, 2, 11, 2, 12, 2, 13, 2, 14, 2, 15, 2, 16, 2, 17, 2, 18, 2, 19, 2, 20, 2, 4, 3, 5, 3, 6, 3, 7, 3, 8, 3, 9, 3, 10, 3, 11, 3, 12, 3, 13, 3, 14, 3, 15, 3, 16, 3, 17, 3, 18, 3, 19, 3, 20, 3, 5, 4, 6, 4, 7, 4, 8, 4, 9, 4, 10, 4, 11, 4, 12, 4, 13, 4, 14, 4, 15, 4, 16, 4, 17, 4, 18, 4, 19, 4, 20, 4, 6, 5, 7, 5, 8, 5, 9, 5, 10, 5, 11, 5, 12, 5, 13, 5, 14, 5, 15, 5, 16, 5, 17, 5, 18, 5, 19, 5, 20, 5, 7, 6, 8, 6, 9, 6, 10, 6, 11, 6, 12, 6, 13, 6, 14, 6, 15, 6, 16, 6, 17, 6, 18, 6, 19, 6, 20, 6, 8, 7, 9, 7, 10, 7, 11, 7, 12, 7, 13, 7, 14, 7, 15, 7, 16, 7, 17, 7, 18, 7, 19, 7, 20, 7, 9, 8, 10, 8, 11, 8, 12, 8, 13, 8, 14, 8, 15, 8, 16, 8, 17, 8, 18, 8, 19, 8, 20, 8, 10, 9, 11, 9, 12, 9, 13, 9, 14, 9, 15, 9, 16, 9, 17, 9, 18, 9, 19, 9, 20, 9, 11, 10, 12, 10, 13, 10, 14, 10, 15, 10, 16, 10, 17, 10, 18, 10, 19, 10, 20, 10, 12, 11, 13, 11, 14, 11, 15, 11, 16, 11, 17, 11, 18, 11, 19, 11, 20, 11, 13, 12, 14, 12, 15, 12, 16, 12, 17, 12, 18, 12, 19, 12, 20, 12, 14, 13, 15, 13, 16, 13, 17, 13, 18, 13, 19, 13, 20, 13, 15, 14, 16, 14, 17, 14, 18, 14, 19, 14, 20, 14, 16, 15, 17, 15, 18, 15, 19, 15, 20, 15, 17, 16, 18, 16, 19, 16, 20, 16, 18, 17, 19, 17, 20, 17, 19, 18, 20, 18, 20, 19]
When you convert to int there is a second parameter that specifies the base, 16 in this case for hex.
Top answer 1 of 4
4
Nice solution, a few suggestions:
- The function name
convert_to_int_arrayseems too general. Consider a more specific name, for example,extract_numbers, or something similar. - There is no need to initialize
results_as_arraytoNone. - Mapping a list of strings to integers:
looks like the job forfor index in range(0, len(results_as_array)): results_as_array[index] = int(results_as_array[index].strip()) return results_as_arraymap:
Since the result ofreturn list(map(int, results_as_array))mapis a generator, it needs to be converted to a list withlist. - Tests: I noticed this line:
testing by changingdraw_result = "04-15-17-25-41" # change to "01-12 + 08-20" or "04-15-17-25-41" or "03-23-27-34-37, Mega Ball: 13" to testdraw_resultmanually it is time-consuming. A better way would be to keep the tests in a dictionary and to useassert. For example:
If you want to explore more "unit testing" have a look at unittest.tests = { "04-15-17-25-41": [4, 15, 17, 25, 41], "01-12 + 08-20": [1, 12, 8, 20], "03-23-27-34-37, Mega Ball: 13": [3, 23, 27, 34, 37] } for lottery_string, expected_output in tests.items(): assert expected_output == convert_to_int_array(lottery_string)
Alternative approach:
- Remove
, Mega Ball: 13if exists - Extract all numbers with a regular expression
import re
def extract_numbers(draw_result):
draw_result = draw_result.split(',')[0]
matches = re.findall(r'\d+', draw_result)
return list(map(int, matches))
2 of 4
5
Marc's answer is an excellent option if you don't care about validation.
If you need to be somewhat sure that the given string represents one of the known formats, then you can pre-bind a match method in a list of pre-compiled regular expressions:
import re
from typing import Iterable
lottery_searches = [
re.compile(pat).match
for pat in (
r'^(\d+)-(\d+)-(\d+)-(\d+)-(\d+), Mega Ball.*
',
r'^(\d+)-(\d+)-(\d+)-(\d+)-(\d+)$',
)
]
def lottery_string_to_ints(lottery: str) -> Iterable[int]:
for search in lottery_searches:
match = search(lottery)
if match:
return (int(g) for g in match.groups())
raise ValueError(f'"{lottery}" is not a valid lottery string')
with output
In[2]: tuple(lottery_string_to_ints('03-23-27-34-37, Mega Ball: 13'))
Out[2]: (3, 23, 27, 34, 37)
In[3]: tuple(lottery_string_to_ints('01-12 + 08-20'))
Out[3]: (1, 12, 8, 20)
In[4]: tuple(lottery_string_to_ints('04-15-17-25-41'))
Out[4]: (4, 15, 17, 25, 41)
In[5]: tuple(lottery_string_to_ints('04-15'))
Traceback (most recent call last):
File "262933.py", line 20, in lottery_string_to_ints
raise ValueError(f'"{lottery}" is not a valid lottery string')
ValueError: "04-15" is not a valid lottery string
Analytics Vidhya
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Top 6 Ways to Convert String to Int in Python
May 20, 2025 - Another method to convert a string to an integer is using the ast.literal_eval() function from the ast module. This function evaluates the given string as a Python literal and returns the corresponding value.
Spark By {Examples}
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Python Convert List of Strings to Ints - Spark By {Examples}
2 weeks ago - How to convert a list of strings to ints in Python? You can use list comprehension or the map() function to convert a list of strings to ints in one line
DaniWeb
daniweb.com › programming › software-development › threads › 274089 › python-converting-string-to-integer
PYTHON: Converting String to Integer!!! [SOLVED] | DaniWeb
April 8, 2010 - firstNumber = int(array[0]) secondNumber = int(array[1]) thirdNumber = int(array[2]) ...#etc. etc. As you can see, this conversion process (from String to Integer) is very inefficient as you must convert each cell one by one... Is there a more efficient alternative solution to this conversion process??? Cheers, ThompsonSensibl · python ·
YouTube
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Converting a String Array to an int Array in Python: A Step-By-Step Guide - YouTube
Discover how to convert a string array of coordinates into an `int` array in Python for your data processing needs, complete with easy-to-follow steps and co...
Published: May 26, 2025
Views: 0
Top answer 1 of 3
3
One way is to use ast.literal_eval.
If you need a numpy integer array, the conversion is trivial.
import numpy as np
from ast import literal_eval
arr_str = '[1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1]'
res = literal_eval(arr_str.replace(' ', ','))
# [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
res_np = np.array(res)
# array([1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1])
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0
arr_str = arr_str.strip("[]")
voila = [int(x) for x in arr_str.split()]
Edit 1: Being pedantic about variable assignment.
Top answer 1 of 2
16
import numpy as np
a = np.array([['-0.99', '', '0.56', '0.56', '-2.02', '-0.96']])
a[a == ''] = 0.0
a = a.astype(np.float)
Result is:
[[-0.99 0. 0.56 0.56 -2.02 -0.96]]
Your values are floats, not integers. It is not clear if you want a list of lists or a numpy array as your end result. You can easily get a list of lists like this:
a = a.tolist()
Result:
[[-0.99, 0.0, 0.56, 0.56, -2.02, -0.96]]
2 of 2
1
That is a pure python solution and it produces a list .
With simple python operations, you can map inner list with float. That will convert all string elements to float and assign it as the zero indexed item of your list.
a = [['-0.99' , '0.56' , '0.56' , '0.56', '-2.02' , '-0.96']]
a[0] = map(float, a[0])
print a
[[-0.99, 0.56, 0.56, 0.56, -2.02, -0.96]]
Update: Try the following
a = [['-0.99' , '0.56' , '0.56' , '0.56', '-2.02' , '-0.96', '', 'nan']]
for _position, _value in enumerate(a[0]):
try:
_new_value = float(_value)
except ValueError:
_new_value = 0.0
a[0][_position] = _new_value
[[-0.99, 0.56, 0.56, 0.56, -2.02, -0.96, 0.0, nan]]
It enumerates the objects in the list and try to parse them to float, if it fails, then replace it with 0.0
Vultr Docs
docs.vultr.com › python › third party › numpy › fromstring()
Python Numpy fromstring() - Convert String to Array | Vultr Docs
November 18, 2024 - The fromstring() function in Python's NumPy library is a powerful tool for converting string data into numerical arrays quickly and efficiently.
YouTube
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Python Tips: Converting a string list to an integer list, in 1 line - YouTube
A simple easy way to turn a list of strings into integers in python, all in one line.
Published: March 8, 2021
Stack Overflow
stackoverflow.com › questions › 68210530 › converting-string-array-into-int-array-in-python
Converting string array into int array in python - Stack Overflow
July 1, 2021 - Initiating read file from another script, I need to get this input as integer, so that I can use it as input to make np.array.
NumPy
numpy.org › doc › 2.0 › reference › generated › numpy.fromstring.html
numpy.fromstring — NumPy v2.0 Manual
If string contains unicode text, the binary mode of fromstring will first encode it into bytes using utf-8, which will not produce sane results. ... Reference object to allow the creation of arrays which are not NumPy arrays. If an array-like passed in as like supports the __array_function__ protocol, the result will be defined by it.
Top answer 1 of 11
1527
Given:
xs = ['1', '2', '3']
Use map then list to obtain a list of integers:
list(map(int, xs))
In Python 2, list was unnecessary since map returned a list:
map(int, xs)
2 of 11
487
Use a list comprehension on the list xs:
[int(x) for x in xs]
e.g.
>>> xs = ["1", "2", "3"]
>>> [int(x) for x in xs]
[1, 2, 3]
GeeksforGeeks
geeksforgeeks.org › python › convert-string-to-integer-in-python
Convert String to Int in Python - GeeksforGeeks
The simplest way to convert a string to an integer in Python is by using the int() function.
Published: June 15, 2026